This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
The 3rd Generation Partnership Project (3GPP) has defined MBMS for the simultaneous delivery of multimedia content to a large set of receivers. A set of MBMS specifications have been published by 3GPP, covering all aspects of the service from the radio access to the content delivery applications and protocols.
MBMS can be split into three general areas—bearer services, delivery methods, and user services and applications. A MBMS bearer service provides a bit pipe for the transport of IP traffic to a group of receivers in an efficient manner. Two delivery methods have been defined in MBMS—streaming and file downloading. The streaming delivery method defines the protocols for the delivery of multimedia content for immediate consumption (e.g., a Mobile TV channel). The file download delivery method enables the file casting of multimedia files for storage and delayed consumption at the receiver. Complementary procedures for describing MBMS user services, for protecting the delivered content, and for enhancing the delivery robustness have also been defined. A MBMS user service is then able to make use of different delivery methods, unicast connections, associated procedures, and MBMS bearer services for providing the desired application to the user.
3GPP Technical Specification (TS) 26.346, Section 11, specifies metadata syntax that is used to describe MBMS user services. The service description may be used to advertise/announce a forthcoming multicast/broadcast event. The service description is primarily used for describing the different delivery methods, the access parameters to the service, and any content protection applied to the service. 3GPP TS 25.346 describes the MBMS Radio Access Network (RAN).
One type of MBMS network is an MBMS over a Single Frequency Network (MBSFN). The MBSFN mode uses a 16-QAM modulation arrangement, e.g., a quadrature amplitude modulation with 16 constellation points. This modulation arrangement provides a much higher bandwidth for MBMS user services than other arrangements. However, MBSFN may not have a large coverage and could be limited to some locations in the MBMS network. The co-existence of regular, e.g., non-MBSFN, MBMS and MBSFN is likely to be needed for at least several years.
In 3GPP Release 7, the media codec requirements were updated in order to enable higher quality services. In particular, the H.264 codec level has been upgraded from 1 b, e.g. QCIF resolution at 128 kbps (kilo-bits-per-second), to 1.2, e.g. CIF resolution at 384 kbps. In order to address the increase in bit rate in the newly specified level, more bandwidth capacity than the capacity provided by regular MBMS bearer services, e.g. 256 kbps, is required. One viable commercial setup involves providing 3GPP Release 6 (Rel-6) terminals with a low quality service that fits their capabilities. Release 7 terminals that support MBSFN can benefit from the increased capacity and receive a higher quality service. Currently a piece of user equipment selects, subject to the availability of MBSFN coverage, the variant of the service that best suits the user's needs.